Within the field of cutting tools used in drilling operations, there are many examples of tool shanks having head receiving pockets with ‘circumferentially open’ central recesses and resiliently displaceable abutment portions.
U.S. Pat. No. 7,360,974 discloses a rotary cutting tool having a tool shank and a replaceable cutting insert. The tool shank includes two longitudinally extending chip flutes and a location opening at the tip of the shank which is open to the chip flutes. The location opening has a circular cross-section. The cutting insert includes a fastening pin having a slightly elliptical cross-section which is inserted into the location opening and rotated into a braced position.
U.S. Pat. No. 7,467,915 discloses a rotary cutting tool having a tool shank and a replaceable cutting head which is installed on and engages a head receiving pocket of the tool shank. The cutting head has a shank connection portion with a dovetail member. The head receiving pocket includes two generally symmetrical castellated wall sections projecting upwardly from a central floor portion. The castellated wall sections include internally facing frustoconical surfaces, and when the dovetail member is rotated into an interlocked position with respect to the head receiving pocket, the dovetail member engages the internally facing frustoconical surfaces.
It is an object of the present invention to provide an improved tool shank having a head receiving pocket with a ‘circumferentially confined’ central recess and resiliently displaceable abutment portions.
It is also an object of the present invention to provide an improved rotary cutting tool in which a cutting head is releasably mounted to the head receiving pocket of the tool shank with a high level of repeatability.